银鹊树胚性愈伤组织继代培养过程中的细胞染色体数目变异

Chromosome Number Variation of Cells in Reiterative Subcultures of Embryonic Callus of Tapiscia sinensis Oliv.

以银鹊树幼嫩的合子胚为外植体诱导胚性愈伤组织,胚性愈伤经增殖后转接到液体培养基中悬浮继代培养,对其多次继代培养的胚性愈伤细胞的染色体数目检测发现：多次继代培养后的胚性愈伤细胞染色体数正常的比例为48.28%（2n=30）,部分细胞出现染色体数目2n=15-60的变异,其变异率高达51.72%,其中以亚二倍体变异为主（40.07%）.结果表明,在体细胞胚胎诱导形成过程中,胚性愈伤组织细胞在染色体水平上发生部分变异,这可能是体胚形成过程中畸形胚产生的根本原因.

The chromosome number of Tapiscia sinensis Oliv. was investigated in both of the root tip cells and embryonic callus cells of subcultures by many times. The results showed that its chromosome number was 2n= 30 in the cells of root tip. Only 48.28% of the cells with normal chromosome number were observed （2n= 30） in embryonic callus. Part of the cells＇ chromosome number varied, the range of those numbers were 15-60,and the frequency of variations was 51.72% ,most of them were hypo-diploid,accounted for 40.07 %. The variation of the chromosome number existed in the embryonic callus maybe was one of the reasons why there were so many abnormal embryoids.